05000361/LER-1983-004, Forwards LER 83-004/01T-0.Detailed Event Analysis Encl

Forwards LER 83-004/01T-0.Detailed Event Analysis Encl

ML20064L603
Person / Time
Site:	San Onofre
Issue date:	01/28/1983
From:	Ray H SOUTHERN CALIFORNIA EDISON CO.
To:	Engelken R NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION V)
Shared Package
ML20064L607	List: 05000361/LER-1983-004, Forwards LER 83-004/01T-0.Detailed Event Analysis Encl 05000361/LER-1983-004-01, /01T-0:on 830116,component Cooling Water Train B Declared Inoperable.Caused by Bent Pickup Contact in Limit Switch LS-5 Preventing Valve from Opening.Switch Contact Repaired,Valve Exercised & Tested Satisfactorily
References
NUDOCS 8302150322
Download: ML20064L603 (2)

LER-1983-004, Forwards LER 83-004/01T-0.Detailed Event Analysis Encl

Event date:
Report date:
3611983004R00 - NRC Website

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January 28, 1983 m n,,,oo i

U. S. Nuclear Regulatory Commission Office o." Inspection and Enforcement l

Region V 1450 Maria Lane, Suite 210 i

Walnut Creek, California 94596-5368 l

Attention:

Mr. R. H. Engelken, Regional Administrator I

Subject:

Docket No. 50-361 14-Day Follow-Up Report Licensee Event Report No.83-004 San Onofre Nuclear Generating Station, Unit 2

Reference:

Letter, H.B. Ray (SCE) to R.H. Engelken (NRC),

dated January 18, 1983 i

The referenced letter provided you with confirmation of our prompt notification, pursuant to Section 6.9.1.12.b of Appendix A, Technical Specifications to Facility Operating License NPF-10, for San Onofre Unit s

2, of a reportable occurrence on January 16, 1983, involving the Containment Cooling System (CCS).

Pursuant to Section 6.9.1.12.b, this submittal provides a written i

l Follow-up Report together with a copy of Licensee Event Report (LER) No.83-004.

On January 16,1983 at 1050 while in Mode 1, Component Cooling Water l

(CCW) Train B was declared inoperable. The CCW heat exchanger saltwater outlet valve would not open after cycling as part of a surveillance test. This rendered the CCS Train B and the Containment Spray System (CSS) Train B inoperable. Since CCS Train A had previously been placed out-of-service, two trains of CCS and one train of CSS were inoperable, exceeding the Action Statements associated with Lc0 3.6.2.3 and LC0 3.0.3 was invoked.

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8302150322 830128

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R. H. Engelken January 28, 1983 The saltwater outlet valve was restored to operable status at 1250 on January 16, 1983 and CCW Train B, CCS Train B and CSS Train B were declared operable. This allowed entry into LCO 3.6.2.3, Action Statement

'a'.

Action Statement 'a' requires that the inoperable train of the CCS be restored to operable status within 7 days.

CCS Train A was restored to operable status at 1300 on January 16, 1983, thus satisfying LC0 3.6.2.3.

Investigations revealed that the rotary contact on Limit Switch LS-5 had a faulty pickup contact which was bent away from its normal position.

This resulted in the inability of the rotor to make proper contact to energize the circuit, thereby resulting in the failure of saltwater outlet valve 2HV-6495 to open. Also, when an attempt was made to open the valve manually and electrically by depressing pushbutton 2HS-6495-2, the valve failed to open du? to binding. A similar failure of this valve occurred on December 28,1982 (see LER 82-174).

It is now concluded that these two causes, faulty limit switch and binding existed with the vcive during both of these events.

The bent limit switch contact was repaired, the valve exercised, tested satisfactorily, and declared operable at 1250 on January 16,1983. No other corrective action to prevent recurrence is planned as this cas an isolated event.

Since no events occurred which called for operation of the affected systems, there was no effect on the health and safety of plant personnel or the public.

Discussions are continuing with the NRC regarding the events surrounding the entry into LC0 3.0.3 on January 16, 1983.

Corrective actions which result from these discussions, and our further analysis of this occurrence, will be provided in separate correspondence.

If there are any questions regarding the above, please contact me.

Sincerely, HS$ /yy%

f Enclosure: LER 83-004 l

A. E. Chaffee (USNRC Resident Inspector, San Onofre Units 2 & 3) cc:

R. J. Pate (USNRC Resident Inspector, San Onofre Units 2 & 3)

U. S. Nuclear Regulatory Commission Office of Inspection and Enforcement U. S. Nuclear Regulatory Commission Office of Management Information and Program Control Institute of Nuclear Power Operations